Device for straightening a strip of semi-rigid material and feeding it into a machine

ABSTRACT

A device ( 1 ) for straightening a strip of semi-rigid material and feeding the strip into a machine, in particular a metallic sheet into a press or the like. The device comprises a lower frame ( 3 ) which carries a set of lower straightening rolls ( 30 ), an upper frame ( 4 ) which carries a set of upper straightening rolls ( 40 ) arranged staggered relative to the lower straightening rolls ( 30 ), and a traction mechanism ( 5 ) for the strip of material arranged both upstream and downstream from the sets of straightening rolls ( 30, 40 ). The device comprises a mechanism for opening and closing ( 7 ) the frames ( 3, 4 ) in order to carry out a function of gripping/releasing the strip of material which is integrated with a mechanism for adjusting ( 6 ) the position of the upper straightening rolls ( 40 ) relative to the lower straightening rolls ( 30 ), both of the mechanisms are designed to move the upper frame ( 4 ) relative to the lower frame ( 3 ) in a translation movement perpendicular to the frames and using guiding elements ( 60 ) of the mechanism for adjusting ( 6 ) the vertical translation.

This application claims priority from French application serial no.08/05757 filed Oct. 17, 2008.

TECHNICAL FIELD

The present invention concerns a device for straightening a strip ofsemi-rigid material and feeding it into a machine, in particular ametallic sheet into a press or the like, the said device comprising atleast a lower frame carrying a set of lower straightening rolls, anupper frame carrying a set of upper straightening rolls arrangedstaggered relative to the lower straightening rolls, traction means forthe strip of material, positioned upstream and downstream from the saidsets of straightening rolls, means for adjusting the position of theupper straightening rolls relative to the lower straightening rolls, andmeans for opening and closing the said upper and lower frames designedso that, in the closed position, the strip of material is grippedbetween the lower and upper straightening rolls and, in the openposition, the strip of material is released from the constraint of thesaid straightening rolls.

PRIOR ART

The term “strip of semi-rigid material” is not limited as such to astrip having a certain width, but also includes a filament, a cable, astranded wire or the like. Similarly the invention applies to any typeof semi-rigid material and, in particular, a metallic sheet. Oneparticular application concerns the processing of metallic sheets woundinto coils, which are fed into lines for cutting, punching, stamping,folding, etc., during the fabrication of metallic components, forexample for the automobile industry. In this field of applicationpresses, or the like, are used which are fed by coil spools, a sheetstraightener that unwinds the sheet from its coil and straightens it toremove its curvature, and a device which feeds the sheet section intothe press, which alternately grips and releases the sheet as a functionof the feeding and cutting cycles of the press.

Depending on the length of the production line, the straightener and thefeeding mechanism are distinct modules separated by a sheet reservoir toensure continuous operation of the press, or they form only one and thesame machine, which is commonly called a “straightener-feeder”, with thesheet reservoir located upstream at the level of the spool.

The invention more particularly concerns that type of machine whichcombines the straightening of the sheet and the feeding of the sheetinto the press. This machine has a function commonly called“grip-release” of the sheet, which is synchronized with the feeding andcutting cycles of the press. During the press-feeding phase, the sheetis gripped between the lower and the upper straightening rolls toundergo the straightening operation. During the sheet cutting orstamping phase in the press, the sheet has to be released fromconstraint, i.e., set free, to enable it to be automaticallyrepositioned in the die of the press.

In current machines, the release function is carried out by opening anupper clamp in a rotary movement about a pivot axis fixed on one side ofthe shutters in the manner of a jaw, or by raising the upper clamp in avertical translation movement along specific guide columns. Thesemovements are generated by hydraulic or electro-mechanical actuators,which necessarily need a supply of energy in order to maintain thegripping position. Such mechanisms are bulky, complex to use and veryburdensome both in terms of the equipment needed and in their energydemand. Moreover, their inertia is high and, for that reason, theircycle rate is limited. They are not suitable for fitting to machinesalready in service. In these machines, the straightening rolls can becarried by a single cradle, which makes it impossible to adjust thepenetration of each of the straightening rolls individually.

Thus, the current systems are not satisfactory.

EXPLANATION OF THE INVENTION

The purpose of the present invention is to overcome the abovedisadvantages by proposing a “straightener-feeder” device with a“grip-release” function, which is realized by means that are compact,simple, economical, reliable, which are characterized by very lowinertia and can therefore operate at high cycle rates, which need noenergy to maintain the gripping position, which can be retrofitted tomachines already in service, and which also allow precise and individualadjustment of the penetration of each of the straightening rolls.

To that end, the invention concerns a device of the type indicated inthe preamble, characterized in that the said means for opening andclosing the said frames are integrated with the said means for adjustingthe position of the upper straightening rolls, being designed to movethe upper frame relative to the lower frame in a translation movementperpendicular to the said frames, and comprising elements for guidingthe said adjustment means in vertical translation.

By virtue of this structure, the mechanical means included are optimizedso as to include the grip-release function in a straightening device,using the function of guiding in vertical translation already present inthe means for adjusting the position of the straightening rolls.

In a preferred embodiment of the invention, the means for opening andclosing the frames comprise a lifting module arranged between the upperframe and the upper straightening rolls, which is coupled to at leastone lifting mechanism designed to move the lifting module and, at thesame time, the upper frame and the upper straightening rolls in verticaltranslation between the said closing and opening positions, andvice-versa.

Advantageously, the lifting mechanism comprises at least one camrotationally driven about a fixed rotation axle by at least oneactuator, the said cam cooperating with at least one roller elementpermanently attached to the said lifting module and comprising a camprofile designed so that the closing position corresponds to a stablecondition of the device and the opening position corresponds to atemporary, unstable condition thereof.

In the preferred embodiment of the invention, the cam comprises twofirst flat sections separated by an angle of about 90° and connected bya first, essentially circular sector, the said cam cooperating with afirst, upper roller element permanently fixed to the lifting module sothat the first, essentially circular sector defines the unstable,opening position of the device and the first flat sections form rollingramps on which the upper roller element circulates between the closingand the opening positions.

Advantageously, the said cam has a second flat section diametricallyopposite the first, essentially circular sector and connected to thefirst flat sections by second essentially circular sectors, this camcooperating with a second, lower roller element permanently fixed to thelifting module and diametrically opposite the upper roller element, suchthat the said second essentially circular sectors define the stable,closed position of the device.

The gap separating the two, upper and lower roller elements fixed on thesaid lifting module is advantageously larger than the largest transversedimension of the cam, and allows a clearance that defines the openingtravel of the said device.

The lifting mechanism can comprise at least one control leverarticulated at one end to the actuator and at the other end to the fixedrotation axle of the cam. In this case, and advantageously, the liftingmechanism has two actuators mounted in opposition on a fixed frame, eachactuator being coupled to the fixed rotation axle of a cam by a controllever, the actuators being mechanically connected so as to function inopposition and combine their forces. These actuators can be chosen fromthe group comprising a bi-stable pneumatic jack, a servomotor, and thislist not being exhaustive.

In the device according to the invention the traction means for thestrip of material preferably comprise specific opening and closing meansand a central control unit is arranged so as to control simultaneouslythe means for opening and closing the frames and the means for openingand closing the said traction means.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention and its advantages will be made more clear by thefollowing description of an embodiment, given as a non-limiting example,with reference to the attached drawings in which:

FIGS. 1 to 3 schematically illustrate the working principle of thedevice according to the invention, respectively in the gripping, releaseand gripping positions,

FIG. 4 shows a perspective view of a device according to the invention,

FIG. 5 is a view similar to that of FIG. 4 showing the device withoutthe frame,

FIG. 6 is a front view of the device in FIG. 4,

FIG. 7 shows a longitudinally sectioned view of FIG. 6 at the level ofthe actuators, and

FIG. 8 is a view of the device in FIG. 4, seen from above.

DETAILED DESCRIPTION OF THE DRAWINGS

Illustrations of the invention and the best way to produce it:

According to the invention, the device 1 for straightening a strip 2 ofsemi-rigid material and feeding it into a machine, in particular ametallic sheet into a press or the like, in a known way, and referringto the figures, comprises a lower frame 3 carrying a set of lowerstraightening rolls 30, an upper frame 4 carrying a set of upperstraightening rolls 40 arranged staggered, relative to the lowerstraightening rolls 30, traction means 5 for the strip 2 of materialarranged upstream and downstream from the said sets of straighteningrolls 30, 40 and means 6 for controlling the vertical position of theupper straightening rolls 40 relative to the lower straightening rolls30, which means comprise elements 60 for guiding each upperstraightening roll 40 in vertical translation.

In the example illustrated, the lower frame 3 is fixed and constitutesthe supporting structure of the device 1 as a whole. It carries a set offour mutually parallel lower straightening rolls 30 aligned in the samehorizontal plane, separated by regular inter-axial distances androtationally driven by an assembly of driving gears 31 which engage withreceiving gears 32 fitted at one end of each lower straightening roll 30(see FIGS. 5 and 7).

In the example illustrated, the upper frame 4 is mobile and carries aset of three mutually parallel upper straightening rolls 40 separated byregular inter-axial distances equal to those of the lower straighteningrolls 30 but offset relative to the latter. The penetration depth ofeach upper straightening roll 40, between two adjacent lowerstraightening rolls 30, can be adjusted in order to adapt the degree ofstraightening to a given strip of material. To enable this, each upperstraightening roll 40 is carried at its two ends by two guiding elements60 which comprise bearings and slide in two grooves 61 provided in thelower frame 3. The position adjustment means 6 comprise, for each upperstraightening roll 40, two threaded rods 62 which extend verticallyacross the said upper frame 4 and which have a lower end 63 engaged witheach guiding element 60 and an upper end 64 which is rectangular so thatit can be moved by a suitable tool 65, which can be manual or automatic.Screwing in and out of the threaded rods 62 lowers or raises thecorresponding upper straightening roll 40. The threaded rods 62 aremechanically coupled by a transmission, with a sprocket 66 and chain 67,to synchronize the movement of the two ends of the same upperstraightening roll 40.

The traction means 5 for the strip 2 of material, arranged upstream anddownstream from the sets of straightening rolls 30, 40, each comprise,in a known way, a fixed lower traction roll 50 carried by the lowerframe 3, and a mobile upper traction roll 51 carried by a bearing 52which slides in a groove 53 of the lower frame 3. An actuator 54, suchas a motor, is coupled to at least one of the lower traction rolls 50,engaging with the drive gears 32 in order to rotationally drive thelower straightening rolls 30. They also comprise means 55 for openingand closing the upper traction roll 51 relative to the traction roll 50,which are arranged so as to grip the strip of material when in theclosed position to move it forward, and to release the strip of materialwhen in the open position. These opening and closing means 55 compriseactuators arranged in line with each end of the upper traction rolls 51and controlled by a central control unit (not shown). In the exampleillustrated, the actuators preferably consist of pneumatic jacks 55whose rod 56 engages with the sliding bearing 52, but they can bereplaced by servomotors or any other known actuator, whether pneumatic,hydraulic or electric.

According to the invention, the device 1 for straightening a strip 2 ofmaterial and feeding it into a machine comprises means 7 for opening andclosing the upper 4 and lower 3 frames arranged so that, in the closedposition, the strip 2 of material is gripped between the lower 30 andupper 40 straightening rolls while, in the open position, the strip 2 ofmaterial is released from the constraint of the straightening rolls 30,40. These opening and closing means 7 of the frames 3, 4 are controlledby the central control unit (not shown) simultaneously with the tractionmeans 5, so that the strip 2 of material is released from anyconstraint.

The opening and closing means 7 differ from the prior art in that theyare integrated with the means 6 for adjusting the position of the upperstraightening rolls 40 and are designed to move the mobile upper frame 4and the upper straightening rolls 40, relative to the fixed lower frame3, and the lower straightening rolls 30 in a translation movementperpendicular to the said frames 3 and 4. To do this, they use theguiding elements 60 for the vertical translation of the adjustment means6. For that purpose they comprise a lifting module 70 arranged betweenthe upper frame 4 and the upper straightening rolls 40, coupled to alifting mechanism 71, 72 designed to move the lifting module 70, alongwith the upper frame 4 and the upper set of straightening rolls 40, invertical translation between the closed position, corresponding to thefunction of gripping the strip 2 of material, and the open position,corresponding to the function of releasing the strip 2 of material.

Referring also to FIGS. 1 to 3, which illustrate schematically theworking principle of these opening and closing means 7, the liftingmechanism comprises at least one cam 71 and preferably two parallel cams71 spaced a distance apart from one another and arranged in the end zoneof the lifting module 70 in order to distribute the forces. Each cam 71is rotationally driven about a fixed rotation axle A by at least oneactuator 72, and the fixed rotation axle A and the actuator 72 iscarried by a fixed frame 73 which is an extension of the lower frame 3.In the illustrated example, the actuator 72 is a bi-stable pneumaticjack. Any other actuator 72 would be suitable, for example a servomotor.In the example shown, the lifting mechanism comprises two jacks 72mounted on the fixed frame 73 in opposition and connected mechanicallyso as to function in opposition and combine their forces. Moreparticularly, each jack 72 is mounted on the fixed frame 73 by anarticulation axis F and the rods 76 of the two jacks 72 are connected toone another by an assembly of articulated stirrups 77. Each cam 71 isrotationally driven by a control lever 78 coupled at one end to thecorresponding actuator 72 by an articulation G provided on one of thestirrups 77, and at the other end to the fixed rotation axle A of thecam 71.

Each cam 72 is arranged between an upper roller element 74 and a lowerroller element 75, consisting respectively of an upper roller and alower roller diametrically opposed and able to rotate about rotationaxles fixed on the lifting module 70 and parallel to the fixed rotationaxle A of the cam 71. The gap E, separating the roller elements 74, 75,is wider than the largest transverse dimension D of the cam 71 andallows a clearance, for example of a few millimeters, which defines theopening travel C of the device 1 (see FIG. 2).

Each cam 71 has a cam profile designed so that the closed position is astable condition of the device 1 and the open position is a temporary,unstable condition thereof. More particularly, each cam 71 has two flatsections 711 separated by an angle of about 90° and connected by a firstessentially circular sector 712, which cooperate with the upper rollerelement 74 fixed on the lifting module 70 in such a manner that thefirst essentially circular sector 712 defines the opening position ofthe device 1 (see FIG. 2) and the first flat sections 711 form rollingramps on which the said upper roller element 74 circulates between theclosing and opening positions. In the closing position (see FIGS. 1 and3), the first flat sections 711, with the upper roller element 74,delimit a clearance corresponding to the opening travel C of the device1.

Each cam 71 also has a second flat section 713, which is diametricallyopposite the first essentially circular sector 712 and is connected tothe first flat sections 711 by second essentially circular sectors 714which cooperate with the lower roller element 75 fixed on the liftingmodule 70 to define the stable closing position of the device 1. In theopening position (see FIG. 2), the second flat section 713, togetherwith the lower roller element 75, delimit a clearance corresponding tothe opening travel C of the device 1. The lifting module 70 is guided invertical translation both by the guiding elements 60 of the upperstraightening rolls 40 and by the lateral parts of the fixed frame 73(which are not shown in the figures).

The operation of the opening and closing means 7 of the device 1 willnow be described with reference to FIGS. 1 to 3 which show, insimplified form and without the traction means 5, the device 1 forstraightening and feeding a strip 2 of material.

In FIG. 1, the device 1 is in a stable, closed position with the strip 2of material gripped between the lower 30 and upper 40 straighteningrolls, undergoing a straightening process during its forward feed. Thejack 72 on the right is in a stable, retracted position and the jack 72on the left in a stable extended position, the control levers 78 areorientated to the right and the cams 71 are in tangential contact ontheir second sector 714 against the lower roller elements 75, keepingthe lifting module 70 in its low position and, at the same time, keepingthe upper frame 4 and the upper straightening rolls 40 in a stable,closed position with no consumption of energy. In this position, theclearance corresponding to the opening travel C is located between thefirst corresponding flat section 711 of the cams 71 and the upper rollerelements 74.

FIG. 2 shows the device 1 in an unstable and temporary position, inwhich the strip 2 of material is released from the constraint of thestraightening rolls 30 and 40 and is no longer moving forward, beingtherefore able to self-center itself relative to the dies of the press.The jacks 72 are working and under pressure, the jack on the right beingin a partially extended position and the jack on the left in a partiallyretracted position, while the control levers 78 have turned throughabout a quarter of a revolution in the direction of arrow R1, moving thecams 71 with them. During such rotation, the second sector 714 of thecams 71 moves away from the lower roller elements 75 and the first flatsection 711 of the cams 71 contacts the upper roller elements 74,causing the lifting module 70 to move vertically up to its highposition, along with the upper frame 4 and the upper straightening rolls40 until, corresponding to the maximum opening travel C, the firstsector 712 of the cams 71 reaches its position defining the unstable,temporary open position with energy consumption. In this position, theclearance corresponding to the opening travel C is transferred tobetween the second corresponding flat section 713 of the cams 71 and thelower roller elements 75.

FIG. 3 shows the device 1 after returning to a stable, closed positionwith the strip 2 of material again gripped between the lower 30 andupper 40 straightening rolls, so as to continue the straighteningprocess during its forward-feed movement. The jacks 72 have continuedworking, in the same direction, and the jack on the right is now in astable, extended position while the jack on the left is in a stable,retracted position, the control levers 78 having continued theirrotation through a quarter-turn in the direction of arrow R2, moving thecams 71 with them. During this rotation the first sector 712 of the cams71 moves away from the upper roller elements 74, which roll over theother first flat section 711 of the cams 71, causing a vertical downwardmovement of the lifting module 70 to its low position along with theupper frame 4 and the upper straightening rolls 40, until the sectionsector 714 of the cams 71 again encounters the lower roller elements 75,which corresponds to the stable, closed position in which no energyconsumption is needed.

To carry out a new grip/release/grip cycle, the jacks 72 are actuated inthe reverse direction. The angular displacement of the cams 71 islimited to an angle of about 90°, which is sufficient to produce thesecycles. In fact, it is easy to see that this mechanism has a very rapidresponse time which enables it to reach high cycling rates.

Possible industrial applications:

The components, sub-assemblies and assemblies constituting the device 1,according to the invention, are made by reproducible industrialprocesses. The device 1 is not limited to straightening a sheet andfeeding the straightened sheet into a press, but can be used for anyother application that requires the functions of straightening andfeeding into any type of machine.

From the above description it emerges clearly that the invention makesit possible to fulfill specific purposes. In particular, it enables thefunction of “gripping/releasing” associated with a straighteningmachine, with the help of an optimized mechanism thanks to which thegripping function is stable and does not require energy input.

The present invention is not limited to the example embodimentdescribed, but extends to any modification and variant that would beobvious to those with knowledge of the field while remaining within thescope of protection defined by the attached claims.

1-10. (canceled)
 11. A device (1) for straightening a strip (2) ofsemi-rigid material and feeding the strip (2) into a machine, inparticular a metallic sheet into a press or the like, the devicecomprising: at least one lower frame (3) which carries a set of lowerstraightening rolls (30), an upper frame (4) which carries a set ofupper straightening rolls (40) arranged staggered relative to the lowerstraightening rolls (30), traction means (5) for the strip of materialarranged both upstream and downstream from the sets of straighteningrolls (30, 40), means for adjusting (6) the vertical position of theupper straightening rolls (40) relative to the lower straightening rolls(30), the means for adjusting (6) comprising guiding elements (60) forthe vertical translation of each upper straightening rolls (40), andmeans for opening and closing (7) the upper (4) and lower (3) framesdesigned such that, in a closed position, the strip (2) of material isgripped between the lower straightening rolls (30) and the upperstraightening rolls (40) and, in an open position, the strip (2) ofmaterial is released from the constraint of the straightening rolls (30,40), wherein the means for opening and closing (7) the frames (3, 4) areintegrated with the means for adjusting (6) the position of the upperstraightening rolls (40) and are designed to move the upper frame (4),relative to the lower frame (3), in a translation movement perpendicularto the frames (3, 4), and comprise guiding elements (60) of theadjustment means (6) in vertical translation.
 12. The device accordingto claim 11, wherein the means for opening and closing (7) the framescomprise a lifting module (70) arranged between the upper frame (4) andthe upper straightening rolls (40), and coupled to at least one liftingmechanism (71, 72) designed to move the lifting module (70) and, at thesame time, the upper frame (4) and the upper straightening rolls (40) invertical translation between the close and open positions, andvice-versa.
 13. The device according to claim 12, wherein the liftingmechanism comprises at least one cam (71) rotationally driven about afixed rotation axle (A) by at least one actuator (72), the cam (71)cooperating with at least one roller element (74, 75) fixed on thelifting module (70) and having a cam profile designed so that the closeposition corresponds to a stable condition of the device (1) and theopen position corresponds to a temporary, unstable condition of thedevice (1).
 14. The device according to claim 13, wherein the cam (71)has two first flat sections (711) separated by an angle of about 90° andconnected by a first essentially circular sector (712), the cam (71)cooperating with a first, upper roller element (74) fixed on the liftingmodule (70) in such a manner that the first essentially circular sector(712) defines the unstable open position of the device (1) and the firstflat sections (711) form rolling ramps on which the upper roller element(74) rotates between the close and open positions.
 15. The deviceaccording to claim 14, wherein the cam (71) has a second flat section(712), diametrically opposite the first essentially circular sector(712) and connected to the first flat sections (711) by secondessentially circular sectors (714), the cam (71) cooperating with asecond, lower roller element (75) which is fixed on the lifting module(70) and diametrically opposite the upper roller element (74) in such amanner that the essentially circular second sectors (714) define thestable, close position of the device (1) and the second flat section(713) forms a clearance zone which defines the opening travel C of thedevice (1).
 16. The device according to claim 15, wherein a gap (E),separating the two, upper (74) and lower (75) roller elements fixed onthe lifting module (70), is wider than the largest transverse dimension(D) of the cam (71), and allows a clearance which defines the openingtravel (C) of the device (1).
 17. The device according to claim 13,wherein the lifting mechanism comprises at least one central controllever (78) articulated at one end to the actuator (72) and at the otherend to the fixed rotation axle (A) of the cam (71).
 18. The deviceaccording to claim 17, wherein the lifting mechanism has two actuators(72) mounted in opposition to one another on a fixed frame (73), eachactuator (72) is coupled to the fixed rotation axle (A) of one cam (71)by a control lever (78), and the actuators (72) are mechanicallyconnected so as to operate in opposition and combine their forces. 19.The device according to claim 13, wherein the actuator (72) is selectedfrom the group comprising a bistable pneumatic jack and a servomotor.20. The device according to claim 11, wherein the traction means (5) ofthe strip (2) of material comprise separate opening and closing meansand the device comprises a central control unit for simultaneouslycontrolling the means for opening and closing (7) the frames (3, 4) andthe opening and closing means of the material strip traction means (5).